Datasheet
V
OUT)
+
V
IN)
(1–β)–V
IN–
(1–β) ) 2V
OCM
β
2β
V
OUT–
+
–V
IN)
(1–β) ) V
IN–
(1–β) ) 2V
OCM
β
2β
V
N
+ V
IN–
(1–β) ) V
OUT)
β
V
OCM
+V
S
V
S
R
S
R
G1
R
G2
R
F1
R
F2
+
R
T
+
-
-
β +
R
G
R
F
) R
G
V
P
+ V
IN)
(1–β) ) V
OUT–
β
V
OCM
R
G
R
G
R
F
R
F
+
+
V
P
V
N
V
OUT-
V
OUT+
V
IN+
V
IN-
-
-
V
OCM
+V
S
V
S
R
S
R
G1
R
G2
R
F1
R
F2
+
R
T
+
-V
S
-
-
THS4500
THS4501
www.ti.com
SLOS350F –APRIL 2002–REVISED OCTOBER 2011
(1)
(2)
(3)
Where:
(4)
Figure 98. Application Circuit for the THS4500
and THS4501, Featuring Single-Supply Operation NOTE: The equations denote the device inputs as V
N
and V
P
, and
the circuit inputs as V
IN+
and V
IN–
. (5)
With a Ground-Reference Input Signal
Figure 100. Diagram For Input Common-Mode
Figure 99. Application Circuit for the THS4500 Range Equations
and THS4501, Featuring Split-Supply Operation
With an Input Signal Referenced at the Midrail
Table 1 and Table 2 depict the input common-mode
range requirements for two different input scenarios,
Equation 1 through Equation 5 are used to calculate
an input referenced around the negative rail and an
the required input common-mode range for a given
input referenced around midrail. The tables highlight
set of input conditions.
the differing requirements on input common-mode
range, and illustrate the reasoning to choose either
The equations allow calculation of the input
the THS4500/1 or the THS4502/3. For signals
common-mode range requirements, given information
referenced around the negative power supply, the
about the input signal, the output voltage swing, the
THS4500/1 should be chosen because its input
gain, and the output common-mode voltage.
common-mode range includes the negative supply
Calculating the maximum and minimum voltage
rail. For all other situations, the THS4502/3 offers
required for V
N
and V
P
(the amplifier input nodes)
slightly improved distortion and noise performance for
determines whether or not the input common-mode
applications with input signals centered between the
range is violated or not. Four equations are required:
power-supply rails.
two calculate the output voltages and two calculate
the node voltages at V
N
and V
P
(note that only one of
these nodes needs calculation, because the amplifier
forces a virtual short between the two nodes).
Table 1. Negative-Rail Referenced
Gain V
IN+
V
IN–
V
IN
V
OCM
V
OD
V
NMIN
V
NMAX
(V/V) (V) (V) (V
PP
) (V) (V
PP
) (V) (V)
1 –2.0 to 2.0 0 4 2.5 4 0.75 1.75
2 –1.0 to 1.0 0 2 2.5 4 0.5 1.167
4 –0.5 to 0.5 0 1 2.5 4 0.3 0.7
8 –0.25 to 0.25 0 0.5 2.5 4 0.167 0.389
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